Illustration by Ryan Rhodes
Illustration by Ryan Rhodes

The latest not-Romney is the strongest one yet. Mitt Romney has beaten back challenges from Rick Perry, Herman Cain and Newt Gingrich in succession.

But in Rick Santorum he faces a rival for the Republican presidential nomination who lacks those candidates’ glaring flaws and has some notable advantages over him.

On paper, the strongest challenger to Romney in the Republican field would have been former Minnesota Governor Tim Pawlenty. Like Romney, Pawlenty was a governor of a blue state; unlike Romney, he won re-election there. His governorship featured nothing as objectionable for Republican primary voters as the health-care law Romney signed in Massachusetts. But Romney never had to face Pawlenty as his principal rival, because he dropped out in August after losing the Iowa straw poll.

Texas Governor Rick Perry entered the race the same weekend as Pawlenty left it, and briefly led the national polls. Support from party conservatives and a strong record as governor of one of the largest states could have made him a strong contender, too -- until he opened his mouth. Republicans stopped supporting him both because they disagreed with his relatively soft-line position on immigration and because they worried that in any debates with President Barack Obama he would defeat himself.

Cain, a former Godfather’s Pizza Inc. chief executive officer, led the polls briefly, too. But even before a series of allegations of sexual harassment and adultery became news, he was showing himself to be ignorant of large areas of public life. He didn’t know the names of foreign leaders, his own position on abortion or the details of his own 9-9-9 tax plan.

Former House Speaker Gingrich had two surges in the polls - - followed by two collapses as Republicans focused on his grandiosity, indiscipline, serial adultery and persistent unpopularity with the public at large.

Leading Challenger

Now Santorum, a former two-term senator from Pennsylvania, has become the leading challenger to Romney by virtue of winning caucuses in Iowa, Minnesota and Colorado, and a non-binding primary in Missouri. He won’t be as easy for Romney to dispatch.

Unlike Perry, Santorum is articulate. Unlike Cain, he has political experience and knowledge of public policy. Unlike Gingrich, he has a personal life that seems to be above reproach. Romney has no advantage over Santorum in any of these respects.

Romney has cited his victory in a statewide election in a blue state to make the case that he can appeal beyond the party’s base. That’s something neither Perry nor Cain nor Gingrich could say. Santorum, on the other hand, won statewide in Pennsylvania, which hasn’t voted for a Republican presidential candidate in 24 years. And he did it twice.

Santorum’s strengths have left Romney resorting to weak attacks. Romney has pointed out that Santorum, like most Republicans who served in the Senate with him, supported such big-spending initiatives as the expansion of Medicare to cover prescription drugs. But Romney’s own health-care law in Massachusetts undercuts any attempt to portray other Republicans as soft on big government.

More recently Romney has gone after Santorum for having supported earmarks. But Santorum no longer supports them. If having previously taken positions that conservatives dislike disqualifies a candidate for the Republican nomination, Romney might as well quit the race now: His past liberal positions easily outnumber Santorum’s.

Romney is also attacking Santorum for having repeatedly voted to raise the debt ceiling, again like most Republicans. Both men, however, take the same (absurd) position on the debt ceiling now: It shouldn’t be increased until two-thirds of the House and two-thirds of the Senate vote for a constitutional amendment that caps federal spending. Romney’s criticism of Santorum may not move voters who have no reason to believe either of them on this issue.

Electability Argument

At some point, Romney will probably turn to the electability argument. He has executive experience, which voters seem to value but Santorum lacks. Santorum’s re-election defeat in 2006 also haunts his candidacy. It was a tough year for Republicans, but the size of Santorum’s loss -- 18 percentage points -- suggests that Pennsylvanians were responding to something about him, not just the national climate.

The electability strategy has drawbacks, too. Republicans have objections to Romney’s record as an executive, and they have doubts about his electability. Santorum has a more appealing biography than Romney: He didn’t grow up as Richie Rich. And Romney won’t win primary votes by saying that Santorum would come across as a social-issues zealot to the wider public, even if it’s true.

Romney is still in the lead. He’s ahead of Santorum in national polls; he has won more delegates; he has much more money; and he remains the only Republican candidate running a national campaign. For the first time, though, he has something else as well: a strong opponent.

(Ramesh Ponnuru is a Bloomberg View columnist and a senior editor at National Review. The opinions expressed are his own.)

To contact the writer of this article: Ramesh Ponnuru at rponnuru@bloomberg.net

To contact the editor responsible for this article: Timothy Lavin at tlavin1@bloomberg.net